Building and funding coal power plants is "irresponsible," US climate envoy John Kerry said Friday, calling "greed" the biggest impediment to climate action.

Kerry also hailed recent talks with China, while offering few details, and called upcoming climate talks in the UAE "absolutely critical".

Speaking in Singapore, the former US chief diplomat said it was now "irresponsible to be funding or building a coal-fired power plant anywhere in the world."

"There's no such thing as clean coal. It's not about to happen," Kerry told the Bloomberg New Economy Forum.

"So we really have to move forward on the coal front," he said, criticising a "business as usual" attitude in much of the world, including the United States.

"We've got to get serious here," he said.

Two years ago at the COP26 meeting in Glasgow countries agreed to "phase-down unabated coal power". Abated generally means to capture emissions before they go into the atmosphere.

And the future of fossil fuels, including coal, is set to be central to discussion at the COP28 meeting later this month.

China produces just over half the world's supply of coal, with domestic production reaching a new record last year, according to the UN.

And current planned production increases in coal and other fossil fuels by the world's largest producers leave the world far off track to keep warming at 1.5C above pre-industrial levels.

Kerry met this weekend with his Chinese counterpart for talks that both sides have called productive, while offering few details.

The pair found "some agreement" on "reducing emissions and the direction we have to go and I'm hopeful about that," Kerry said Friday. 

The talks were seen as key to setting the stage for COP, which Kerry called "absolutely critical to open up the opportunity to keep 1.5 degrees alive."   

"Oil and gas we hope will be at the table and that's critical because we can't win the battle without it," he added.   

Among the contentious subjects on the table at Dubai will be the details of a so-called loss and damage fund to compensate the poorest nations as they cope with the consequences of climate change, going beyond simple assistance for adaptation.

The United States and some other developed countries have been wary of the fund, avoiding setting targets for its size and keen to dodge any suggestion that historical emitters have an obligation to pay into it.

Still, Kerry said Washington would contribute "several millions of dollars," and there was now a "sense of the way forward".

A much-debated draft proposal on the shape of the fund was agreed last week, despite extensive wrangling over whether it would be hosted by the World Bank. For now, the proposal suggests the Bank, whose largest contributor is the United States, as a temporary home.